The specific instruction in Deuteronomy 16:16 is that, during the three holy day seasons of the year, we should not appear before God "in vain" or "with futility." The context refers to how God has blessed us, and since God's blessings are far more than just physical, the application of this principle to other areas of life is extensive. Concluding that our obligation ended with a monetary offering on the holy days would be a serious error. David explains why in Psalm 40:6-8:

Sacrifice and offering You did not desire; my ears You have opened. Burnt offering and sin offering You did not require. Then I said, "Behold, I come; in the scroll of the book it is written of me. I delight to do Your will, O my God, and Your law is within my heart."

David recognizes that God is not interested in the sacrifices and offerings in the long run. He instituted them because of the sins of the people, and they served as a tutor—a schoolmaster—to point Israel to their Messiah (Galatians 3:19-25). Jeremiah 7:22-23 echoes this principle:

For I did not speak to your fathers, or command them in the day that I brought them out of the land of Egypt, concerning burnt offerings or sacrifices. [He instituted them at a later time.] But this is what I commanded them, saying, "Obey My voice, and I will be your God, and you shall be My people. And walk in all the ways that I have commanded you, that it may be well with you."

God mentions here the essence of the Old Covenant: "I will be your God, and you shall be My people." Israel considered this acceptable because of what they could get out of the arrangement. But when God defined the terms and explained what it meant for Israel to be His people—the fact that the Israelites now had to obey His voice and walk in His ways rather than their own—they rebelled. For this reason, God instituted the sacrifices and offerings to remind them regularly of their obligations to Him and their neighbors.

Returning to Psalm 40:6-8, David understood that God was not ultimately concerned about the rituals and the forms. They had their place as a means to an end, but they were not the end. David writes something similar to what God says through Jeremiah. Notice in verse 8 that he delights to do God's will and that God's law is in his heart. After stating that the sacrifices and offerings are not God's primary interest, he then tells what is: eager obedience to God's will, expressed through His law in particular and His Word in general.

God is not after our pocketbooks, and those of His servants who emulate Him will not be either. Every last thing of value we have to offer has its source in Him, and He distributes it according to His will. We have nothing to give Him that He has not already given to us (I Corinthians 4:7).

No, what God is after is our hearts. He is interested in our character, our attention, and our regard for Him and the other parts of His creation. He cannot instantaneously create these kinds of things. Because God's Word has gone forth (Isaiah 55:11), those things are being created, and so progress or its lack can be seen. Three seasons of each year, He asks us to come before Him so that He—and we—can see what His Word is accomplishing in us and how His creation is prospering.

Despite the sacrifices that God instituted for Israel not being principal elements of His purpose, they still play a part in what He is working out. Remember, none of God's words are unimportant. If He gives a command, He requires that it be fulfilled. Anciently, some of the sacrifices and offerings that Israelites gave supported the priests and the Levites. They helped to maintain the Tabernacle and the Temple so that the people could be represented before God. They also served to remind the people of God's providence and blessing in their lives, which applies just as well to us today.

But just as the animal sacrifices were a type, a symbol, of the work the Messiah would later do, so also freewill offerings, while important themselves, are also symbolic of something much more significant. When God instructs us not to come before Him empty, it contains a spiritual application concerning the words God spoke on the sixth day of Creation (Genesis 1:26), and the spiritual image into which He is forming us (II Corinthians 3:18).

In principle, He is saying, "Do not come before Me in futility or without a recognition of what My Word is accomplishing in your life." We can put it another way: "Come before Me with the spiritual fruit—the fruit of the Spirit—that I have been cultivating in you. Show Me the character that is developing. Demonstrate the faith, hope, and love that you are receiving from Me. Manifest what My Word is accomplishing and prospering in your life."

The Israelites could not have wasted their time during the growing season and expected to have something to harvest—and offer—for the holy days. Likewise, we risk coming before God in vain or with futility during the festivals if we have not been working with Him all along to cultivate spiritual fruit. Producing the spiritual qualities that God is interested in requires ongoing submission to Him, and it takes time. If He cannot develop those things in us overnight, surely neither can we!

When we obey the command not to come before Him empty, void, or without producing any effect, the physical application is easy. The spiritual counterpart is more difficult and far more critical. It requires us to be aware at all times of the words spoken thousands of years ago, words that are prospering within God's purpose this very moment. It obliges us to look continually for God's signature, to keep His written creation top of mind, and to submit to His will with a pure heart every step of the way.